Scroll fluid machine

ABSTRACT

A scroll fluid machine comprises a body having a driving shaft, an electric motor coupled to the driving shaft, and a blower. The blower cools the body, a connection between the body and motor, and the electric motor by wind from the blower.

BACKGROUND OF THE INVENTION

The present invention relates a scroll fluid machine such as a scroll compressor or a scroll vacuum pump.

A scroll fluid machine comprises a driving shaft driven by an electric motor and having an eccentric axial portion; an orbiting scroll rotatably mounted to the eccentric axial portion via a bearing and having an orbiting wrap on an orbiting end plate; a fixed scroll having a fixed wrap on a fixed end plate to form a sealed chamber between the orbiting wrap and the fixed wrap; and a self-rotation-preventing device for preventing the orbiting scroll from rotating on its own axis.

The orbiting scroll is eccentrically revolved with the eccentric axial portion of the driving shaft and the self-rotation-preventing device to gradually reduce volume of the sealed chamber toward its center of the orbiting scroll to compress fluid sucked from the outer circumference or to gradually increase it outward to decompress fluid sucked at the center to discharge it from the outer circumference.

With operation of the scroll fluid machine, not only a driving electric motor but also a bearing of the driving shaft, a bearing of the eccentric axial portion of the driving shaft, the self-rotation-preventing devices and a portion contacting an opposite surface of a tip seal in a groove of the end of the orbiting wrap are heated to decrease its performance and to shorten its life. Thus, it is necessary to cool the parts effectively not to raise temperature to more than fixed temperature.

As a method for cooling a scroll fluid machine with air, JP2001-123969A discloses that a fan is mounted to an output shaft of an electric motor coupled to a fluid machine body, the fan being turned with the electric motor to blow air toward the motor and the body, and JP8-21392A discloses that three fans driven by auxiliary electric motors are disposed at front and both sides of the fluid-machine body to blow toward the body.

The former enables the electric motor to be cooled by a blower at some extent, but air heated by the electric motor is blown toward the fluid machine body thereby making it impossible for the body to be cooled efficiently.

The latter generates cooling wind by the auxiliary electric motors to enable each part to be blown suitably, but in addition to the electric motor for the body itself, the three auxiliary electric motors, fans and mounting structures therefor are required, which is uneconomical and increases it whole size. Also, cooling winds are mixed to each other to decrease desired cooling efficiency.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a scroll fluid machine in which a fluid-machine body, an electric motor and a connection between the body and motor are efficiently cooled, structure of the machine being simple, its whole size being the minimum.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the invention will become more apparent from the following description with respect to embodiments as shown in accompanying drawings wherein:

FIG. 1 is a side elevational view of the first embodiment of a scroll fluid machine according to the present invention;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a vertical sectional view taken along the line IV-IV in FIG. 3;

FIG. 5A is an exploded perspective view of a cooling fan;

FIG. 5B is a perspective view of the assembled fan;

FIG. 6 is a top plan view of the second embodiment of a scroll fluid machine; and

FIG. 7 is a view of the third embodiment of a scroll fluid machine and a control system thereof according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 to 5 show the first embodiment of the present invention. In the following description, in FIGS. 1 and 2, the left side is deemed “the front”, while the right side is deemed “the rear”.

A scroll fluid machine comprises a body 1; an electric motor 2 joined to the rear (the right of FIGS. 1 and 2) of the body 1; and a blower 3 disposed to one side of the body 1.

In FIG. 4, the body 1 comprises a fixed scroll 5 having an inlet 5 a at the upper front part, an outlet 5 b at the center and a fixed wrap 4 at the rear surface; a housing 6 around the fixed scroll 5; a driving shaft 7 rotatably mounted in s boss 6 a in the middle of the rear side via a bearing 6 b; an orbiting scroll 8 rotatably mounted around an eccentric axial portion 7 a at the front end of the driving shaft 7 to allow an orbiting wrap 9 thereof to engage with the fixed wrap 4 to form a sealed chamber; and three crank pins 10 each of which constitutes a self-rotation-preventing device the front end of which is rotatably mounted to the orbiting scroll 8. Only one of the crank pins 10 is shown in FIG. 4.

The driving shaft 7 is turned by the electric motor 2 to allow the orbiting scroll to revolve thereby forming the sealed chamber between the fixed wrap 4 and the orbiting wrap 9, so that air taken in through the inlet 5 a is compressed and discharged from the outlet 5 b.

A number of cooling fins 11, 12 are provided on the front surface of the fixed scroll 5 and the rear surface of the orbiting scroll 8 to diffuse heat involved with compression.

A number of cooling fins 13 a are provided on the outer circumferential surface of a housing 13 for the electric motor 2. A front end plate 13 b of the housing 13 is bolted to the rear of the housing 6 for the body 1.

The front end of a rotationally-driving output shaft 14 projecting forward from the center of the end plate 13 b is joined to the rear end of the driving shaft 7 via a shaft coupling 15 to allow the power to be transfered from the electric motor 2 to the driving shaft 7.

In FIGS. 1-3 and FIG. 5, the blower 3 comprises a box-like thin support 16 fixed to one side of the housing 6 with a plurality of screws (not shown) and extending a connection between the body 1 and the electric motor 2 or boss 6 a covering the shaft joint 15; a short-depth cylindrical hood 19 coupled to the circumference of a circular opening 17 in the middle of the support 16 and having a plurality of grilles 18; a blowing fan 21 in the hood 19 to turn around an axis perpendicular to the side of the body 1; a fan-driving flat electric motor 21 an output shaft of which is coupled to the rear surface of the blowing fan 20; and a plurality of support stays 22 fixing the fan-driving electric motor 21 at the center in the hood 19.

An upper stay 22 a of the support stays 22 acts as streamlined guide which allows part of wind generated by the fan-driving electric motor 20 to flow toward the electric motor 2, thereby enabling wind to flow not only to the side of the body 1 but also to the shaft coupling 15 between the electric motor 2 and the body 1 at the optimum separation rate at the same time. Thus, a single blower 3 can cool the body 1, the connection between the body 1 and the motor 2 and the motor 2 effectively. Also the blower 3 is disposed at the side of the body 1 thereby facilitating the structure and minumizing the whole size.

The number of the guide 22 a is not limited to one, but may be increased depending on the optimum separation rate of blowing amount to the body 1 and the electric motor 2 or may be omitted.

FIG. 6 shows the second embodiment of the present invention, in which the same numerals are allotted to the same members and description thereof is omitted.

In the second embodiment, a fluid machine body 1 is disposed close to and substantially in parallel with an electric motor 2 and a cylindrical blower 30.

The blower 30 comprises a casing 31 which has an outlet 31 a facing the body 1, a connection between the body 1 and the electric motor 2 and the electric motor 2; a blowing fan 33 such as cross-flow fan or a sirocco fan rotatable around a shaft 31 almost in parallel with the body 1; and a fan-driving electric motor 34.

It enables wind to blow toward the body 1, the connection between the body 1 and the electric motor 2 and the motor 2 and enables them to be cooled efficiently.

FIG. 7 shows the third embodiment of the present invention, in which the same numerals are allotted to the same members as those in the first embodiment and description thereof is omitted.

In the third embodiment, temperature sensors 23, 24 are attached on a fluid machine body 1 and an electric motor 3 respectively. The temperature sensors 23, 24 are input to a control 26 via leads 23 a, 24 a and an A/D converter 25.

Predetermined temperature data are stored in the control 26 and compared by the control 26 with detected data in the temperature sensor 23, 24. When the detected data is less than the predetermined temperature, it turn off a fan-driving electric motor 21 or 33. When it is more than the predetermined temperature, it turns on the fan-driving electric motor 21 or 33.

In the foregoing embodiments, the blowing fans 20, 33 and fan-driving electric motors 21, 34 are disposed in the vicinity of one side of the fluid-machine body 1, but the present invention is not limited thereto. Instead, in the vicinity of the fluid-machine body 1, there may be provided an outlet for blowing out wind produced by rotation of blowing fans toward the fluid-machine body 1, a connection between the body 1 and the electric motor 2 and motor 2.

A plurality of flow-shifting plates are provided to shift cooling wind to part requiring to be cooled thereby enabling wind produced by the blowing fans 13 a, 20 to be transferred to the fluid-machine body 1, electric motor 2 and the connection between the body 1 and the motor 2 at distribution rate corresponding to required heat-releasing amount. The distribution ratio corresponding to required heat-releasing amount means to increase blowing amount to part where a lot of heat is released to decrease blowing amount to part where heat is not so released. The flow-shifting plate is manually changed to direct in a predetermined direction, or changed with power such as a motor toward part where a lot of heat is released based on temperature detected by the temperature sensors 23, 24.

The foregoing merely relates to embodiments of the present invention. Various changes and modifications may be made by those skilled in the art without departing from the scope of claims wherein: 

1. A scroll fluid machine comprising: a body comprising a driving shaft comprising an eccentric axial portion, an orbiting scroll having an orbiting wrap rotatably mounted to the eccentric axial portion, and a fixed scroll having a fixed wrap engaging with the orbiting wrap to form a sealed chamber between the orbiting wrap and the fixed wrap; an electric motor operatively connected to the driving shaft of the body; and a blower at one side of the body to blow wind toward the body, a connection between the body and the electric motor, and the electric motor.
 2. A scroll fluid machine of claim 1 wherein the blower comprises a housing; a mounting plate fixed to the housing; a cylindrical hood mounted to a peripheral edge of an opening of the mounting plate; a blowing fan in the hood; and a fan-driving electric motor coupled to the fan; and a plurality of stays fixing the fan-driving electric motor at a center of the hood.
 3. A scroll fluid machine of claim 2 wherein an upper stay of said plurality of stays acts as streamlined guide which allows part of wind generated by the fan-driving electric motor to flow toward the electric motor, thereby enabling wind to flow not only the side of the body but also to the connection between the electric motor and the body.
 4. A scroll fluid machine of claim 2 wherein the blower is disposed in parallel with a longitudinal direction of the body and the electric motor, and comprises a casing and a blowing fan in the casing, the casing having an outlet facing the body, a connection between the body and electric motor and the motor to allow wind therefrom to blow onto and cool them.
 5. A scroll fluid machine of claim 2, further comprising a control; a first temperature sensor attached on the body and connected to the control; and a second temperature sensor attached on the electric motor and connected to the control, the control starting operation of the fan-driving electric motor to move the fan when temperature detected by one of the sensors is higher than predetermined temperature 